Blade for safety razors



Feb. 4, 1930. R. E. THOMPSON 1,746,063

BLADE FOR SAFETY RAZORS Filed June 4 1924 \q. 6 7o 72 U 9 11 W Fi .2..

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Patented Feb. 4, 1930 UNITED STATE PATEN OFFICE? I p g e. ,RAI PH E., TEOMP SQN, OF BROOKLINE, MASSACHUSETTS, ASSIGNOR T0 GILLETTE v SAFETY RAZOR COMPANY, OF BOSTON, MASSACHUSETTS, A. CORPORATION OF DEM-'- WARE BLADE FOR SAFETY R AZORS My invention relates. to safety razors of the type in which a blade havingtw'o opposite cutting edges is combined with a holder having two guards adapted to cooperate respectively with the two cutting edges of the blade. In razors of this type as heretofore constructed it has been the practise to provide the blade with apertures located midway betweenthe cutting edges and adapted to receive positioning devices carried by the holder and located midway between the two guards, so as to render it immaterial whether one blade edge or the other'is used in connection with"either guard. Further, in the manufacture of these blades it has been customaryto make use of the same apertures for positioning the blades in the machines by which the cutting edges are formed, with the result that the reversal of a, blade edge for edge in these machines has no eflectupon thecharacter of the cutting edge produced, or

upon its position relative to theline on which the apertures are centered. In accordance vwith the present invention the blade apertures above referred to are displaced laterally to a very slight extent, so that they are no longer symmetrically located with respect 'to the cutting edges of the blade, and by thus displacing these apertures I produce 'a blade of which the edges, when-the bladeis used in a holder of the type .above referred to, will g have difierent exposures with'respect to thecorresponding guards and, if sharpened by means of machines such as are now in use for the purpose, willdifl'er slightly in respect to the angles between the bevels which form the edges, with. the result that the blade is adapted to give a better shave than heretofore for the reasonhereinafter, explained In the accompanying drawing, in which my invention is illustrated as applied to a double-edged blade'of the flexible type' Figure l is a plan view of'the blade, the

dimensions being enlarged for ,the sake of clearnes's;

Figure 2 is a similarly-enlargedtransverse section through the blade combin'edwith the adjacent parts (if a holder; and p F igure 3 illustrates diagrammatically the formation of the blade edges.

eral displacement of the line 5' with respect to the longitudinal center of the blade, indi-- cated by the line 6, is exaggerated in the drawing, the actual displacement being preferably about ten thousandths vofan inch. The

center hole 7 is not used for positioning pur- -"poses, so that if made of suflicient size it does not need to be displaced.

The holder illustrated clamping cap 8 provided with pins 9 adapt- 1 F comprlses a bladeed to pass respectively through the apertures 4 in the blade and position the latter without permitting appreciable play of the blade laterally, a blade-supportingplate 10 provided on each of its longitudinal edges with a, guard 11 and with holes 12 for the reception of the pins 9, and a handle; 13- shown in part only, the holder being of a familiar type in which the blade when in use is clamped between the parts 8 and 10 and is curved transversely when clamped. The pins 9 and holes 12, of

which only one of each is shown, are centered on lines which are equidistant from the uards 11, and consequently the cutting edges of the blade when combined with theholder are displaced laterally with respect to the corresponding guards to an extent substan-- tially equal to the displacement of the line 5 r With respect to the line 6, Figure 1.

' [The result of the displacement just referred to is that the blade edges?) and 3' have different exposures with respect to the corresponding ards 11, the exposure of the edge 3' being greater than that of the edge 3. This is illustrated in Figure 2, in which the lines ea and 6 5 indicate approximately the planes, of contact ofthe two sides of the razor with the face in shaving, and the distance cc indicates the extent to which the exposure of the edge 3' exceeds that of the edge 3, the distance cc being exaggerted I to correspond with the distance between the lines 5 and 6 in Figure 1, The practical 'effeet. of the difference between theexposures of the edges 3 and 3' in the use ofthe razor is that the edge 3, because of its minimum ex-' first with the edge 3 and then with the edge 3', the user is enabled to obtain a better, shave than is otherwise obtainable without changing the clamping adjustment of the blade.

In Figure 3,14 indicates a rotary abrading cylinder and 15 and ,16 indicate the bladeclamping parts of a blade holder provided with upright pins 17 adapted to pass through the apertures 4 in the blade 2 andthereby position it during the application of its edges 20 to thecylinder 14.7 Only one of the pins 17 is shown, the other being directly behind it, and it is to be understood that the parts 15 and 16 are suitably mounted so-as to be capable of an up and down movement in the direction of the axes of the pins 17 so that the blade edge which is being'operated upon by the cylinder l twill be-supported by the periphery of the latter. Assuming that the blade 2 is held between the parts 15 and 16 in the position shown in full lines, in which the edge being operated upon its farther from the center line of the positioning apertures in the blade than is the other edge, the result of the edge-forming operation will be that the edgebeing operated upon, which will become the edge 3' of the finished blade, will be beveled on asharper angle than will be produced when the blade is reversed edge for edge between the parts 15 and 16, as indicated in dotted lines,vto produce the edge 3. The reason for this is that the angle "of the bevel depends upon the direction of movement of the surface of the cylinder 14 at the point where the edge portion of the blade rests upon it, and'this direction ofmovement makes a greater angle with the plane of the bladewhen the latter is in the dotted-line position than when it is in the full-line position. Consequently the edge 3, having the blunter angle as well as the less exposure when the blade is used for shaving, will be less delicate and more durable than the edge 3, and therefore better adapted for the re apertures located in a line parallel to said edges, but unequally spaced between them, the edge furthest from the positioning apertureshaving a relatively long bevel and the other edge having a relatively short bevel.

2. As a new article of manufacture, a detachable safety razor blade having two par? allel cutting tively long evel anda sharp angle, the other having a relatively short bevel and azblunt angle, and means on the blade for positioning edges, one edge having a relasaid blade in a symmetrically formed razor adapted to receive double edged blades in such manner that said sharp angled edge has i agreater exposure than the blunter edge.

3. The combination with a symmetrical blade holder comprising cap, guard and hanvdle portions adapted normally to receive, position ahd retain a blade having two parallel edges and. two positioning apertures,

one ad'acent to either end and a third aper ture midway between the first two, of a blade havingtwo cutting edges and three apertures located in a line parallel to saidedges, said line being unequally distant from the cutting edges andthe edge further from said line having a longer bevel than the other edge.

4. In a safety razor, the combination with a symmetrical guard and a cap having studs for positioning a flexible double edged blade, of a blade having positioning apertures and a central aperture for the studs all disposed in a line closer to one edge of the blade than the other, the respective edges being also of "different character and comprising an edge 'produced by-the intersection of two long bevels. and an edge produced by the intersection of two short bevels, the former being located further from the line of the positioning apertures than the latter.

Signed at Boston, Massachusetts, this second day of June, 1924.

RALPH E. THQMPSON,

moval of the beard without giving a close shave, while the edge 3', being formed on a sharper angle, will be more delicate and bet:

ter adapted for the finishing or close shave.

produced when the face is gone over the second time. The effect of the displacement of p the positioning apertures in the blade in respect to its cutting edges is therefore twofold, assuming that these apertures are utillzed in positioning the blade during the sharpening process, inasmuch as the formation of the edges is thereby varied in such a 

